The music in the movie was written by David Raskin. The music that played as the movie ended—no words, just music--was a song called "Kansas". Although Raskin composed most of the music in the movie, he didn't write this final tune from scratch. He adapted it from music in a 1938 movie called "The River". I don’t know whether or not he realized that the music in that movie wasn't original, but had also been adapted from an older song: "How Firm a Foundation". So, while many people were feeling a sense of utter and complete hopelessness as the movie ended, Christian people ended with not just the tune but the words of the song ringing in their minds. The Providence of God? Perhaps. One verse to the song says,
When through fiery trials thy pathway shall lie,
My grace, all-sufficient, shall be thy supply;
The flame shall not harm thee; I only design
Thy dross to consume and thy gold to refine.